Now you can blame your parents for all those one-night stands you've had. According to a new study, a tendency toward promiscuity lies partially in genetic make up. And all this time, jerks were saying you just had low self-esteem.

Researchers from the online open-access journal PloS One have linked slutiness to a version of a dopamine receptor gene called DRD4. (Interestingly, this same gene has also been linked to alcoholism, political liberalism and a love of horror films.) Of the 181 participants in the study, it was found that those with this "thrill-seeking" variant of DRD4 were twice as likely to report a history of one-night stands as those without it.

"The motivation seems to stem from a system of pleasure and reward, which is where the release of dopamine comes in. In cases of uncommitted sex, the risks are high, the rewards substantial and the motivation variable—all elements that ensure a dopamine 'rush,'" says study researcher Justin Garcia, a postdoctoral fellow at Binghamton University, State University of New York.